314 G. B. WISLOCKI AND T. J. PUTNAM 



and enlargement of the head were quite remarkable. An extreme 

 dilatation of the ventricles and thinning of the cortex were fre- 

 quently observed within ten days. 



The present study was undertaken to determine whether sub- 

 stances injected into the dilated and occluded ventricles undergo 

 absorption and, if they do, how they escape from the ventricles 

 into the tissues of the brain. This question has to some extent 

 been considered by several of the previous investigators. Dandy 

 and Blackfan ('13, '17) described the results of injecting phenol- 

 sulphonephthalein into the ventricles of fifteen human beings 

 suffering from internal hydrocephalus of the obstructive type. 

 After injection the time of appearance and the amount of the 

 drug in the urine were noted. They found that after injection 

 of phenolsulphonephthalein into the dilated ventricles from 0.5 

 to 2 per cent of the drug was excreted in the urine within the 

 lirst two hours. Excretion of the dye commenced from 20 to 45 

 minutes after injection and continued for many days. Their con- 

 'Clusion is that in obstructive hydrocephalus practically no absorp- 

 \tion takes place from the ventricles. 



In the present study hydrocephalus was established experi- 

 mentally in animals, and several substances, the absorption of 

 which could be studied histologically, were subsequently injected 

 into the dilated ventricles. A solution of potassium ferrocyanide 

 and iron ammonium citrate, which can be readily precipitated 

 as Prussian blue in the tissues, and trypan blue, were selected 

 for injection into the dilated ventricles. The method chosen 

 for producing the hydrocephalus was the one described by Weed 

 because the technique is relatively simple and hydrocephalus 

 develops promptly. 



The experiments were performed upon kittens and young 

 rabbits. A total of twenty-five animals was used, consisting of 

 fifteen kittens and ten rabbits. The kittens ranged in age from 

 two to six weeks, the rabbits from one to three weeks. Weed's 

 technique was closely adhered to. A 5 to 10 per cent suspension 

 of lampblack in physiological salt solution was prepared. The 

 animals were anesthetized, the skin shaved, and a needle inserted 

 through the occipito-atlantoid ligament into the cisterna cere- 



